This invention relates to an apparatus for the attachment of plastic container carriers to the peripheral edges of a plurality of containers such as for soft drinks, which carriers are of sheet form and adapted to bind the plurality of containers together for convenience in carrying.
Among the carrier devices adapted to bind the peripheral edges of a plurality of containers standing side by side on their flat ends for the purpose of convenience in carrying, there is included a plastic container sheet carrier. The sheet carrier has a plurality of openings each surrounded by an annular portion. In the remaining intervening spaces of the sheet carrier, there are provided two grip holes adapted for insertion of the fingers.
In an ordinary container such as a can for a soft drink, both or at least one of the opposite ends of the container has its end surface slightly bent inwardly except for the peripheral edge which circumferentially surrounds the end. The circumferential edge has a diameter slightly greater than the diameter of the main portion of the container which lies underneath. In most cases, these containers are made of aluminum.
The openings in the sheet carrier have a diameter smaller than the diameter of the main portion of the container. This carrier, therefore, is attached to the containers by forcibly expanding the annular portions of the openings to enlarge the openings and allow the peripheral edges of the containers to slide past the annular portions, then allowing the annular portions to resume their original shape thereby causing the inner surfaces of the annular portions to come into tight contact with the outer surfaces of the main portions of the containers. After the sheet carrier has been attached as described above, the user has only to insert his thumb and index finger into the grip holes and take hold of the remaining portion of the sheet carrier. In this manner, he can carry the containers conveniently without requiring a holder as would otherwise be required in carrying the plurality of containers.
As described above, the sheet carrier of such a construction proves to be highly useful. One problem which has been encountered by the conventional sheet carrier concerns the procedure involved when the openings are forcibly expanded out in effecting the attachment of the carrier to the containers. This forcible outward expansion of the openings, when made with the finger tips on all the containers, requires a considerable amount of force, though it is not impossible. From the standpoint of operational efficiency and in consideration of the large number of openings involved, such a manual procedure proves substantially impracticable.
To cope with the situation, therefore, there has been suggested a device capable of mechanically effecting this work (U.S. Pat. No. 3,628,305). This device is adapted so that two pins are inserted inside a pair of opposed openings and the pair of openings are expanded outwardly. This device, consequently, has the disadvantage that the annular portions tend to be torn, expanded unevenly, and brought into contact with the outer surfaces of the containers with insufficient tightness. Besides, this device entails a serious problem that when the pins are removed after the ends of the containers have been inserted into the expanded openings, the pins, which must be of great rigidity, tend to scratch the containers, possibly to the extend of impairing their commercial value.
The inventor, therefore, proposed a method and apparatus capable of enabling a sheet carrier to be efficiently attached to containers without the possibility of causing breakage in the sheet carrier and inflicting scratches upon the lateral surfaces of the containers (U.S. patent application Ser. No. 104,926).